Honestly, if you can't split a particular piece of wood with a 25 ton splitter, you should just put that chunk into a bonfire pile. Anything of the size you are describing will split easily, given that isn't chock full of knots. Most knots can be managed by carefully sawing the wood before it gets to the splitter (assuming you're running the saw).
I've kinda retired from the wood splitting business, but now my teenage boys do most of the splitting using a Fiskars splitting axe. Oak, cherry, walnut, hickory, maple and black locust all bust up pretty easy if the old man saws it right.
Ridin' 'cross the desert. . .